Protective building structure

ABSTRACT

A protective structure having a plurality of independent alarm circuits adapted for use adjacent to a window or the like opening in a building wall. The structure includes a frame and a plurality of insulating members secured within the frame. Each of the insulating members defines an opening for receiving an electrical conductor therein. Since each of the insulating members may be fractured by the application of a predetermined amount of force thereon, for example by an intruder, a rupturing of the electrical conductor by the fracturing of the insulating member will cause an alarm to be actuated. The frame defines a pair of perimetric recesses about the outer periphery thereof to accommodate conductors therein so that if the frame is ruptured, an alarm will likewise be sounded. The conductors in one recess are in circuit with the conductors in certain of the insulating members, while the conductors in the other recess are in circuit with the conductors in the remaining insulating members so that a pair of independent circuits are provided. A plurality of tamper switches are also disposed in the device so that attempts to remove the protective structure from the opening in the building wall will also actuate an alarm. Thus, the structure is effective against attempts to remove the structure, to sever its frame, or break through the opening defined by the frame.

11 3,725,891 1 51 Apr. 3, 1973 [54] PROTECTIVE BUILDING STRUCTURE Elton W. Miller, 285 Franklin St., Harrisonburg, Va.

22 Filed: Sept. 8, 1970 21 Appl.-No.: 7 0,158

[76] Inventor:

5 7 ABSTRACT A protective structure having a plurality of independent alarm circuits adapted for use adjacent to a window or the like opening in a building wall. The structure includes a frame and a plurality of insulating members secured within the frame. Each of the insulating members defines an opening for receiving an electrical conductor therein. Since each of the insulat- [52] U.S. Cl ..340/273 ing members may be fractured by the application of a [51] lnt. Cl. ..G08b 13/08, G08b 13/12 predetermined amount of force thereon, for example [58] Field of Search ..340/273, 274, 276; 200/52 D by an intruder, a rupturing of the electrical conductor by the fracturing of the insulating member will cause [56] 1 References Cited an alarm to be actuated. The frame defines a pair of perimetric recesses about the outer periphery thereof UNITED STATES PATENTS to accommodate conductors therein so that if the 585 171 6/1897 Arnold 340/273 frame is ruptured, an alarm will likewise be sounded. 3 05l935 8/1962 'i: ":3 The conductors in one recess are in circuit with the 6 5 5 Masomb 340/273 conductors in certain of the insulating members, while 9/1895 Alexander u 340/273 the conductors in the other recess are in circuit with 2,101,040 12 1937 Hayley et al.... ..340 273 the conductors in the remaining insulating members so 181,078 8/1876 Larner ..340/273 that a P Of independent circuits are provided- A plurality of tamper switches are also disposed in the p y Exam-mp4,) Caldwe" device so that attempts to remove the protective struc- Assistant Examiner scott R Partridge ture from the opening in the building wall will also ac- Atmmey Lane Aitken Dunner & Ziems tuate an alarm. Thus, the structure is effective against attempts to remove the structure, to sever its frame, or

break through the opening defined by the frame.

8 Claims, 6 Drawing Figures a ALARM SUPP LY 7o 1 7' 65d 50 \SOO 74 I 50b 9 soc. 741- F -71. I i 71b 771 J n770 '/JI 77c g 78) IALARM L PATH-HljUAFR3 1m sum 1 0F 2 INVENTOR ELTON W. MILLER 4 M @aww v ORNEYS PROTECTIVE BUILDING STRUCTURE BACKGROUND OF THE INVENTION This invention relates to a protective building structure. More particularly, this invention relates to a pro tective building structure capable of being mounted adjacent a window or the like in an opening in the building wall and including a plurality of alarm-actuating circuit means therein. Still more particularly, this invention relates to a protective building structure which includes electrical circuit means which are capable of actuating an alarm upon removal of the structure, breaking of any one of a plurality of insulating members accommodating a conductor in the structure, or by fracturing the frame of the structure.

For ages, it has been a problem to provide a suitable alarm mechanism to prevent ingress into a building structure by unauthorized personnel. Thus, the art has produced a number of alarm systems and devices which have as their general object the desire to actuate an alarm when unauthorized attempts are made to enter a building.

While a variety of alarm systems are satisfactory for their purposes when the alarm is incorporated into the building structure at the time it is erected, it is an additional problem to adapt an existing building structure to accommodate a suitable alarm system. Thus, the art has produced a number of protective screens which are adapted to be mounted over a window or other openings in a building. An example of such a device may be seen in U.S. Pat. No. 3,051,935 to C. P. Willson.

In developing such a device, it is an aim to provide a protective structure which has an aesthetically pleasing appearance and which effectively conceals the presence of the alarm system or electrical conductors therein. Moreover, it is an additional aim of such devices to be readily adapted to existing building structures without the necessity of making any or substantial modifications to the existing structure.

While a number of protective structures of this general type have been developed, no single structure appears to be effective against the three probable ways in which an intruder would seek to defeat the protective structure. In general, an intruder would be likely to break through the opening in the protective structure and through the glass of the window to gain entrance to the building. A second attempt at entry may be by an attempt to remove the structure from the opening leaving the window or the like unprotected. Still another likely method of attempting to gain access is to attempt to sever the frame member, such as by cutting. Some examples of prior art which seeks to overcome some of the problems solved by this invention, but which are largely ineffective against all three methods of access or which use substantially different approaches may be seen in the following U.S. Pats: No. 438,127 to W. J. Ackerman; No. 585,171 to W. T. Arnold; No. 1,003,234 to A. Cline; No. 1,252,834 to C. Pastore; No. 1,995,082 to F. H. Stotts; and No. 2,101,040 to E. Bayley et al.

Accordingly, it is an object of this invention to provide a protective structure adapted to be used in an opening in a building.

It is another object of this invention to provide an aesthetically pleasing protective structure which is readily capable of utilization in existing alarm systems.

It is still another object of this invention to provide a protective structure which includes a plurality of conductors in a grid of fracturable members disposed in an array in an opening in a building wherein an alarm will be sounded upon fracturing any one of the insulating members and rupturing the conductor therein.

It is still another object of this invention to provide a protective structure which includes at least a pair of independent conductors which are effectively concealed about the perimeter of the frame and which are arranged so that an alarm will be actuated when the frame is cut or severed. I

It is still another object of this invention to provide a protective structure which utilizes tamper switches in combination with the grid-like arrangement and perimetric conductor system previously mentioned so that an alarm will be actuated when the protective structure is removed from the opening in the building.

These and other objects of this invention will become apparent upon review of the accompanying drawing when taken together with the following written description of the invention.

BRIEF SUMlVlARY OF THE INVENTION Directed to overcoming the shortcomings of the prior art and achieving the aims and objects aforestated, this invention relates to a protective structure which is adapted for use adjacent a window or the like in an opening in a building wall. The structure includes a frame having a plurality of insulating members secured to the frame. Each of the insulating members is characterized as being capable of fracture by the application of a predetermined amount of force thereon. Conductors are included within the insulating members which are disposed in a grid-like array across the opening in the building, so that when one of the fracturable, insulating members is fractured, an alarm is actuated.

The frame includes a pair of recesses about the perimeter thereof to accommodate at least a pair of conductors therein which are in circuit with certain conductors within the openings in the insulating members. Preferably, the conductors in one of the recesses are in an electrical circuit with the conductors in certain of the insulating members and are electrically independent from the conductors in the second recess. The conductors in the second recess are in circuit with the conductors in the other of the insulating members and are electrically independent from those in the first recess to provide an added measure of safety for the operation of the structure through the use of at least a pair of independent circuits. The perimetric alarm system is effective against attempts to cut or sever the frame of the structure to gain access to the building.

A plurality of tamper switches comprising normally open contacts are in a spaced relationship with a face of the structure and in circuit with certain conductors located therein so that the alarm will be actuated by removal from the protective structure from the building.

A protective structure according to the invention is adapted to be used in an opening in an existing building structure and is capable of ready attachment to existing alarm systems.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a perspective view of the protective structure according to the invention located adjacent an existing window in a building wall;

FIG. 2 is a front elevational view of the protective structure according to the invention;

FIG. 3 is an end view of the protective structure ac cording to the invention taken along line 3-3 of FIG.

FIG. 4 is a fragmented view of the cross-section of the structure taken along line 44 of FIG. 3;

FIG. 5 is a partial view in perspective of a portion of the building structure according to the invention illustrating the cooperation of the insulating members, the conductors, and perimetric recesses therein; and

FIG. 6 is a circuit diagram of the electrical conductors in circuit with an alarm and supply to form a protective system utilizing the structure according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, a protective building structure according to the invention is designated generally by the reference numeral 10. The structure 10 is illustrated as mounted adjacent an existing window 11 in a building situated in an opening designated generally by the reference numeral 12 defined-by a building wall 13. The structure according to the invention may also be used over openings in doors, ventilators, and the like.

The structure 10 is defined by a rigid frame designated generally by the reference numeral 15 which comprises a pair of generally horizontal frame members 16 and 17 which are rigidly secured, such as by a mortise and tenon arrangement, to a pair of vertical frame members 19 and 20 to form an integral frame. In the embodiment shown in FIG. 1, the structure is provided with additional rigidity by the utilization of an intermediate support member 22 which is generally horizontally disposed at about the midpoint of the vertical frame members 19 and 20.

Additional integrity is provided to the structure 10 by a pair of vertically upstanding intermediate support members 24 and 25 which together with the intermediate horizontal support member 22 divide the structure 10 into a plurality of window-like segments designated generally by the reference numeral 27. The number of intermediate horizontal and vertical members within the frame is a function both of the size of the frame and the desired aesthetic effect desired by the user. Thus, FIG. 1 is illustrative of one embodiment of the invention.

As can be seen in FIG. 2, the structure 10 defines only four segments 27, rather than six as shown in FIG. 1. For illustration of one means for securing the intermediate members to the frame members, horizontal member 22 includes a plurality of tenons 28 which are received in appropriate mortises defined by the vertical frame members 19 and'20 respectively. Similarly, the vertical intermediate frame member 29 includes a'plurality of tenons 30 which are received in mortises defined by the horizontal members 17 and 16 respectively.

While the frame 15 and the intermediate supports are preferably made from wood, other materials such as plastics, metal and the like will also achieve the aims of the invention.

A plurality of generally vertically extending, insulating tubular members are designated generally by the reference numeral 32. A plurality of similar insulating tubular members which are generally horizontally extending within the structure 10 are designated generally by the reference numeral 33. The tubular members 32 are preferably made from a plastic and are generally hollow to define an opening to accommodate a conductor, preferably an insulated conductor therein. As will be seen in the discussions of FIGS. 5 and 6, the vertically disposed tubular members 32 preferably accommodate a single insulated conductor in circuit with one circuit, for example the positive circuit, of an alarm system. Similarly, the horizontal tubular members 33 preferably accommodate a single insulated conductor which is in circuit with the other circuit of a source of supply, for example, the negative circuit.

The tubular members 32 and 33 are sized to accommodate readily the conductors disposed therein. It is a characteristic of the members 32 and 33 that upon contact by an intruder or an object wielded or thrown by an intruder, the members 32 and 33 will fracture and will cause .the conductors therein to break or separate to sound an alarm system. As will be seen, the circuit arrangement is such that the alarm will be sounded if any one of either the horizontally extending or vertically extending tubular members are severed and the conductor therein broken.

It is a feature of this invention that the presence of conductors within the tubular members 32 and 33 is not detected by the observer. Thus attempts of an intruder to break through the tubular members 32 and 33 to gain access to the building will cause an alarm to be actuated under the conditions described without alerting the intruder to this fact.

As may be seen in FIG. 2, the opposed ends of the vertically-extending members 32 are received in openings substantially in register in the horizontally-extending frame members 16 and 17 respectively. In such an instance, the tubular member 32 is a single unitary element which passes through an opening 35 in the horizontally-extending intermediate member 22. If desired, the tubular member 32 could consist of a pair of similar members each of which having a length which extends between the frame member 16 and the intermediate frame member 22 while the other tubular member extends between the intermediate frame member 22 and the frame member 17. In either instance, the overall operation of the circuit is the same.

Similarly, the horizontally-extending tubular members 33 may extend between the frame member 19 and the frame member 20, the end portions of the tubular members 33 being received in openings which are substantially in register in the frame members 19 and 20. As previously described, if desired, the horizontally-extending member 33 may comprise two or more elements spanning only the distance between the external frame member and an intermediate frame member. As shown in FIG. 2, the length of span would be between frame member 19 and the frame member 29 and between the frame member 29 and the frame member 20.

The structure further defines a pair of substantially parallel, perimetric recesses 40 and 41 which traverse the entire periphery of the structure 10 defined by the frame members 16, 17, 19 and 20.

The purpose of the perimetric recesses 40 and 41 is to accommodate insulated conductors therein since conductors located in the recesses 40 and 41 are in series circuit with the alarm means. An attempt by an intruder to sever only any one of the frame members to gain access to the building would cause an alarm to be actuated. Accordingly, it is the second significant feature of the protective structure 10 that it will fustrate the attempts of an intruder to gain access to the build ing by attempting to cut or fracture the frame member, in addition to attempts to break through the tubular structure 32 and 33, as previously described.

A third significant aspect of the structure 10 is the utilization of a plurality of tamper switches designated generally by reference numeral 50, and specifically by reference numerals 50a through 50d. The tamper switches are preferably located in recesses 49 located near the comer of the frame members on the reverse face thereof.

Each tamper switch 50 is a normally open switch having a biased contact 51. As shown in the phantom outline in FIG. 3, the biased contact 51 may be depressed to such a position that it closes the tamper switch which is in series circuit with the alarm system.

When the structure 10 is in position against the window 11, for example, each of the tamper switches 50 will have its biased contact 51 in the depressed state shown in the phantom outline 52 in FIG. 3. The dashed line 54 in FIG. 3 illustrates the forward extent of the existing window structure 11 for contact by the biased contact 51 of each tamper switch 50. When so positioned, a series circuit is established between conductor 74e and conductor 74a of the tamper switch. Switches of the type described are commercially available and include a terminal 59 to which is secured the conductor 74e and a terminal 60 to which is secured the conductor 74a to form a series circuit therebetween when the member 51 is in the position designated by the phantom outline 52.

A plurality of terminal blocks designated generally by the reference numeral 65, and specifically by numerals 65a 65e, are disposed respectively in the frame members 19 and near the upper and lower portions thereof. The terminal blocks are located to provide a convenient binding post for attachment of the conductors of an existing alarm system. Preferably, a pair of terminal blocks 65a and 65d which are about in register in the upper portion of the frames 19 and 20 are provided to receive a positive signal from a source of supply and in circuit with an alarm, while the other pair of terminal blocks 65b and 65c, for example at the lowermost edges of the frame members 19 and 20, are provided to receive a negative signal from a source of supply and are in circuit with an alarm.

Other convenient means for interconnecting the alarm of the protective structure to an existing alarm system may also be used. For example, the unit may be provided with a plurality of lengths of conductors so that the unit may be wired to the alarm system at a point remote from the structure of the invention.

The details of a representative wiring diagram are shown in FIG. 6. The tamper switches designated generally at 50 in FIG. 3 are designated by reference numerals 50a 50d in FIG. 6. The terminal blocks designated generally at 65 are designated by reference numerals 65a 65d in FIG. 6. The terminal block 65a and the tamper switch 50a are located in the upper portion of the vertical frame member 20, while the tamper switch 50b and the terminal block 65b are located in the lower portion thereof. Similarly, the tamper switch 50c and the terminal block 65c are located in the lower portion of the frame member 19, while the terminal block 65d and the tamper switch 50d are located in the upper portion thereof.

It is preferred that the circuit components be located in such a manner that a pair of independent circuits are provided. Thus, a series circuit is located between a source of positive supply and an alarm means 71, which include each of the tamper switches 50a, 50b, 50c, and 50d, together with the terminal blocks 65a and 65b. In addition, the conductors which are disposed are preferably located in the vertical tubular members 32. Thus, a lead 72 provides a source of signals to the terminal block 65a. A conductor 74 is connected to the terminal block 65a in such a manner that a plurality of portions designated by reference numeral 74a are located within adjacent tubular members 32.

The portions of the conductor designated 74b are located in a portion of the recess 40 which is located in lower frame member 17, while the portion of the conductors designated 740 is located in the portion of the recess 40 located in the upper frame member 16. In this manner, a continuous conductor having verticallyoriented sections 74a located in tubular member 32 is threaded throughout the length of the frame member.

It will be noted that the portion of the conductor designated 74e traverses the entire length of frame member 16 in recess 40 while the portion of the conductor designated 74f traverses the entire lower portion of the frame member 17. In addition, the conductor 74g traverses the entire length of the frame member 19 in recess 40 through terminal block 65d. Accordingly, the recess 40 will contain a pair of conductors in an overlapping relationship. The exact detail of the disposition of the conductors depends upon a number of factors such as whether the number of verticallydisposed tubular members 32 is odd or even. Since it is desirable to have at least one strand of the conductor in recess 40 about the entire perimeter of the frame 15 within recess 40, the wiring detail is achieved with this end in mind. It should be understood that conductor 74e will overlap intermittently within recess 40 in frame 16 with portions of the conductor designated by numeral 74c, while the conductor 74f will intermittently overlap the portions of the conductor designated by the numeral 74b in the frame member 17 within recess 40.

A negative source of supply 76 is provided in circuit with a conductor 77 to form a series circuit with alarm 78. It is preferred that the negative alarm circuit be threaded through the horizontal tubular members 33 in a manner similar to that described above. Thus, the portions 77a of the conductor are located within the tubular members 33 while the portions of the conductor designated 77b are located in the recess 41 in the frame member 20, while the portions of the conductor designated 77c are located in the recess 41 in the frame member 19. The portion of the conductor designated 77d is located in the recess 41 in the frame member 17, while the portion of the conductor designated by the reference numeral 77e is located in the recess 41 in the upper frame member 16 along its entire length. Conductor 77f is located in recess 41 in frame member 19 and is in circuit with the terminal block 65c. In this manner, the series circuit is provided between the source of supply 76 and the alarm 78 so that if any one of the conductors is severed orseparated, alarm 78 will be actuated. The wiring technique thus described provides a circuit independent between the positive series circuit and the negative series circuit. In this manner, one circuit will be operative, even if the other is inoperative or has been disconnected, for example, by an intruder.

It should be understood that the sources of supply 70 and 76, as well as the alarms 71 and 78, are located in situ and the structure according to the invention is adapted to be incorporated into existing alarm systems which are actuated by any discontinuity in the electrical series circuit between the source of supply and the alarm. Thus, breakage of the conductor by fracturing either the tubular members 32 or 33, severing of any conductor located in either recess 40 or 41, or removal of the structure 10 from the frame so that the tamper switches 50a through 50d are actuated will cause the alarm to be actuated.

Returning now to the discussion of FIG. 3, it will be understood that the upper portion of FIG. 3 illustrates tamper switch 50d and terminal block 65d while the lower portion of FIG. 4 illustrates tamper switch 500 and the terminal block 650. The portions of the conductors there depicted have been illustrated using the same reference numerals used in FIG. 6, so that the manner of wiring is clear.

FIG. 4 is a view taken along line 4-4 of FIG. 3 showing the frame member 19 in cross section and defining recesses 40 and 41 having conductors located therein. The relationship of the tubular members 33 with the vertical tubular members 32 is also shown reflecting that the horizontally-extending members 33 are spaced forward of the members 32 and have conductors located therein. The frame member 19, as do frame members 16, 17, and 20, defines a U-shaped slot 80, the base of which defines the recesses 40 and 41.

FIG. 5 is a view in perspective taken of a portion of the alarm device according to the invention showing the manner in which the conductors having the same reference numerals as were used in FIG. 6 are threaded in the tubular members 32 and 33 and cooperate with the recesses 40 and 41 in the frame members. The openings in the frame members through which the conductors pass are designated generally by the reference numeral 90.

Both thehorizontal and vertical conductors may also respectively traverse U-shapedslots 85 and 86 in the intermediate frame members 22 and 29. When the conductor is located within such a slot, it is preferred that a filler such as an epoxy cement or a filler strip of wood or another suitable material be placed over the conductors to conceal their presence. By this technique, attempts by an intruder to sever only the intermediate members will be frustrated.

What is claimed is:

1. A protective structure adapted for use in an opening in a building wall comprising:

a frame which defines at least one recess about substantially theentire periphery thereof to accommodate a conductor in a substantial portion of said recess, plurality of insulating members secured to said frame and spaced within an opening defined by said frame, each of said insulating members being capable of accommodating a conductor therewithin, said plurality of members being characterized in that each of said members is readily fractured by the applicationof a predetermined amount of force thereon during attempts to pass through said opening,

circuit means, including a first conductor disposed within a first predetermined number of said insulating members, for actuating an alarm when a portion of said conductor is severed by the fracturing of one or more of said insulating members, said circuit means further including a second conductor disposed about the periphery of said frame so that said circuit means operates to actuate an alarm when said second conductor is severed by the breakage of said frame said second conductor traversing substantially entirely the periphery of the frame, and a third conductor disposed within a second predetermined number of insulating members, said second predetermined number being different from said first predetermined number of said insulating members, said circuit means thus defining a first circuit and a second circuit which are electrically independent of each other, and

at least one tamper switch in circuit with said circuit means and arranged so that said alarm will be actuated by the action of said circuit means in response to said tamper switch when said frame is removed from the opening in the building wall.

2. The structure as defined in claim 1 wherein each of said insulating members is a hollow tubular member disposed between opposed portions of said frame.

3. The structure as defined in claim 2 wherein said frame defines a first pair of spaced members and a second pair of spacedmembers, and a pair of spaced recesses about the periphery of said frame, said first pair of spaced members and said second pair of spaced members cooperating to define said opening; and wherein said tubular members are disposed within said frame so that a first plurality of tubular members are substantially parallel to said first pair of frame members and a second plurality of said tubular members are sub stantially parallel to said second pair of frame members, and wherein said first conductor is disposed within each of said first plurality of frame members, said second conductor is disposed in one of said pair of recesses, and said third conductor is disposed within each of said second plurality of tubular members and communicates with a substantial portion of the second recess in said frame.

4. The structure as defined in claim 3 wherein said frame includes an intermediate support member, said support member defining a recess to accommodate a conductor therein.

5. The structure as defined in claim 3 further including a source of supply and an alarm in circuit with said 7. The circuit as defined in claim 6 wherein at least one tamper switch is in circuit with one of said first circuit and said second circuit so that one of said first alarm and said second alarm will be actuated when said frame is removed from the opening in the building wall.

8. The circuit as defined in claim 3 further including a first pair of terminal blocks in circuit with said first circuit and a second pair of terminal blocks in circuit with said second circuit. 

1. A protective structure adapted for use in an opening in a building wall comprising: a frame which defines at least one recess about substantially the entire periphery thereof to accommodate a conductor in a substantial portion of said recess, a plurality of insulating members secured to said frame and spaced within an opening defined by said frame, each of said insulating members being capable of accommodating a conductor therewithin, said plurality of members being characterized in that each of said members is readily fractured by the application of a predetermined amount of force thereon during attempts to pass through said opening, circuit means, including a first conductor disposed within a first predetermined number of said insulating members, for actuating an alarm when a portion of said conductor is severed by the fracturing of one or more of said insulating members, said circuit means further including a second conductor disposed about the periphery of said frame so that said circuit means operates to actuate an alarm when said second conductor is severed by the breakage of said frame said second conductor traversing substantially entirely the periphery of the frame, and a third conductor disposed within a second predetermined number of insulating members, said second predetermined number being different from said first predetermined number of said insulating members, said circuit means thus defining a first circuit and a second circuit which are electrically independent of each other, and at least one tamper switch in circuit with said circuit means and arranged so that said alarm will be actuated by the action of said circuit means in response to said tamper switch when said frame is removed from the opening in the building wall.
 2. The structure as defined in claim 1 wherein each of said insulating members is a hollow tubular member disposed between opposed portions of said frame.
 3. The structure as defined in claim 2 wherein said frame defines a first pair of spaced members and a second pair of spaced members, and a pair of spaced recesses about the periphery of said frame, said first pair of spaced members and said second pair of spaced members cooperating to define said opening, and wherein said tubular members are disposed within said frame so that a first plurality of tubular members are substantially parallel to said first pair of frame members and a second plurality of said tubular members are substantially parallel to said second pair of frame members, and wherein said first conductor is disposed wIthin each of said first plurality of frame members, said second conductor is disposed in one of said pair of recesses, and said third conductor is disposed within each of said second plurality of tubular members and communicates with a substantial portion of the second recess in said frame.
 4. The structure as defined in claim 3 wherein said frame includes an intermediate support member, said support member defining a recess to accommodate a conductor therein.
 5. The structure as defined in claim 3 further including a source of supply and an alarm in circuit with said circuit means so that said alarm is actuated by said circuit means when one of said conductors comprising a portion of said circuit means is interrupted.
 6. The circuit as defined in claim 3 further including a first source of supply and a first alarm in circuit with said circuit means, and a second source of supply and a second alarm in circuit with said circuit means, said first source of supply, said second source of supply, said first alarm, and said second alarm being arranged to define said first circuit and said second circuit.
 7. The circuit as defined in claim 6 wherein at least one tamper switch is in circuit with one of said first circuit and said second circuit so that one of said first alarm and said second alarm will be actuated when said frame is removed from the opening in the building wall.
 8. The circuit as defined in claim 3 further including a first pair of terminal blocks in circuit with said first circuit and a second pair of terminal blocks in circuit with said second circuit. 